A group III nitride semiconductor is a promising material for a light emitting device in an ultraviolet to visible region and a next-generation advanced electronic device.
In order to make semiconductor devices integrated, it is necessary to form a region with different conductivities in an in-plane direction.
However, it has been known that it is very difficult to perform conductivity control on a very hard material system such as a group III nitride semiconductor by ion implantation after crystal growth.
Conventionally, for example, Japanese Patent No. 3430206 discloses a process for producing a semiconductor device which carries out local conductivity control using mass transport without using ion implantation.
Here, the above described mass transport will be briefly described.
The mass transport is a phenomenon that some of the atoms forming a crystal move by heating and the atoms are rearranged so as to reduce surface free energy.
It has been known that when a concave and convex structure is formed on a semiconductor surface and heated to a predetermined temperature or higher, mass transport occurs, which causes a phenomenon that the corners of the concave and convex structure are rounded or filled up.
A theory and an experimental result of the mass transport are disclosed in Journal of Applied Physics Vol. 67, pp. 2434 (1990), for example.